In the face of that, Wildlife Services still chases off 80 percent of the animals it encounters, rather than killing them, she said.

The agency targets specific animals that prey on sheep, cattle and other species and doesn't indiscriminately kill predators, said Lyndsay Cole, a Wildlife Services spokeswoman in Fort Collins, Colo.

Most of them are coyotes -- nationally and in Oregon: 83,695 in fiscal 2011, a 3 percent increase from the year before, the figures show.

"We try very hard to make sure the balance of wildlife is maintained," Cole said.

Sheep, cattle vulnerable

Malheur County sprawls across an immense 9,926 square miles of mountains, desert, alkali and sagebrush -- about the size of Maryland, but with only 31,313 people.

"I think Wildlife Services has done a really good job here in Malheur County," said Dan Joyce, chairman of the county commissioners. He believes the federal agency's presence is essential to a depressed rural economy where livestock revenues total roughly $100 million per year.

"I've ridden up on a cow giving birth and the coyotes were eating the calf," said Joyce, 58, who comes from a ranching background and spent half his life on horseback.

"In Malheur County, you have sheep that never outgrow their vulnerability to coyote attacks," said Dave Williams, Oregon director of Wildlife Services in Portland.

His agency -- with about 50 employees in the state -- kills coyotes by using foothold traps, neck snares, aerial gunners and a spring-loaded device loaded with sodium cyanide called an M-44. Despite those control efforts, "the coyote population has probably never been healthier than now," he said.

Critics: Agency obsolete

Mark Salvo, a spokesman for WildEarth Guardians, said the government wastes money killing coyotes. The best available science shows female coyotes compensate for government control programs by giving birth to more pups more often, he said.

"Coyotes are a perfect example of how misguided the federal killing programs are," he said.

The group's report said Wildlife Services spent about $1 billion between 2004 and 2011 to kill animals.

That's a direct subsidy to agriculture and other private interests, the report said.

Bannerman, the Wildlife Services' spokeswoman in Washington, said the $1 billion also paid for disease surveillance and rabies prevention programs, hazing birds from airport runways to prevent their being sucked into jet intakes and causing crashes, and other non-lethal programs.

Last week, Wildlife Services captured and relocated a sow grizzly with cubs in Montana that killed 70 domestic sheep, instead of killing it, she said.

The money also goes to control other species such as alligators, brown tree snakes (an invasive species notorious for devastating native bird populations) and monk parakeets (tropical birds that build giant nests on utility poles, sometimes causing fires and power outages), Wildlife Services officials said.

One of the program's success stories in Oregon has been the federally threatened snowy plover, Williams said. The nesting success of plovers on the state's beaches is the highest since monitoring began in 1990 because the agency targets avian and mammalian predators, he said.

The animal rights group argues that the century-old Wildlife Services has outlived its usefulness and its successful campaigns involving animals like the plover and monk parakeets could be assigned to other agencies.